ramstage: prepare for relocation

The current ramstage code contains uses of symbols that cause issues
when the ramstage is relocatable. There are 2 scenarios resolved by this

1. Absolute symbols that are actually sizes/limits. The symbols are
   problematic when relocating a program because there is no way to
   distinguish a symbol that shouldn't be relocated and one that can.
   The only way to handle these symbols is to write a program to post
   process the relocations and keep a whitelist of ones that shouldn't
   be relocated. I don't believe that is a route that should be taken
   so fix the users of these sizes/limits encoded as absolute symbols
   to calculate the size at runtime or dereference a variable in memory
   containing the size/limit.

2. Absoulte symbols that were relocated to a fixed address. These
   absolute symbols are generated by assembly files to be placed at a
   fixed location. Again, these symbols are problematic because one
   can't distinguish a symbol that can't be relocated. The symbols
   are again resolved at runtime to allow for proper relocation.

For the symbols defining a size either use 2 symbols and calculate the
difference or provide a variable in memory containing the size.

Change-Id: I1ef2bfe6fd531308218bcaac5dcccabf8edf932c
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2789
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
9 files changed